Kinematics of a Young Low-mass Star-forming Core: Understanding the Evolutionary State of the First-core Candidate L1451-mm

• Autores: Maureira, María José; Arce, Héctor G.; Dunham, Michael M.; Pineda, Jaime E.; Fernandez Lopez, Manuel; Chen, Xuepeng; Mardones, Diego
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Star formation; Low mass
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We use 3 mm multiline and continuum CARMA observations toward the first hydrostatic core (FHSC) candidate L1451-mm to characterize the envelope kinematics at 1000 au scales and investigate its evolutionary state. We detect evidence of infall and rotation in the NH2D(11,1-10,1), N2H+(1-0), and HCN(1-0) molecular lines. We compare the position-velocity diagram of the NH2D(11,1-10,1) line with a simple kinematic model and find that it is consistent with an envelope that is both infalling and rotating while conserving angular momentum around a central mass of about 0.06 M o. The N2H+(1-0) LTE mass of the envelope along with the inferred infall velocity leads to a mass infall rate of approximately 6 ×10-6 M o yr-1, implying a young age of 104 years for this FHSC candidate. Assuming that the accretion onto the central object is the same as the infall rate, we obtain a minimum source size of 1.5-5 au, consistent with the size expected for a first core. We do not see any evidence of outflow motions or signs of outflow-envelope interaction at scales ≳2000 au. This is consistent with previous observations that revealed a very compact outflow (≲500 au). We conclude that L1451-mm is indeed at a very early stage of evolution, either a first core or an extremely young Class 0 protostar. Our results provide strong evidence that L1451-mm is the best candidate for being a bona fide first core.
Fil: Maureira, María José. University of Yale; Estados Unidos
Fil: Arce, Héctor G.. University of Yale; Estados Unidos
Fil: Dunham, Michael M.. State University of New York at Fredonia; Estados Unidos
Fil: Pineda, Jaime E.. Max Planck Institut Fur Extraterrestrische Physik; Alemania
Fil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina
Fil: Chen, Xuepeng. Chinese Academy of Sciences; República de China
Fil: Mardones, Diego. Universidad de Chile; Chile